Water-soluble coatings packages and methods for making and using same

ABSTRACT

THIS INVENTION IS DIRECTED TO COATED COMPOSITIONS COMPRISING GRANULAR DETERGENT SOLIDS OR DETERGENT TABLETS COATED WITH A WATER-SOLUBLE PARTIAL ESTER OF (A) A NONIONIC HYDROXYL-CONTAINING MICELLE-FORMING SURFACE ACTIVE AGENT AND (B) A VINYL-ALEIC ANHYDRIDE INTERPOLYMER, AND THE PROCESS FOR PRODUCING SAID COATED COMPOSITIONS.

United States Patent 3,630,920 WATER-SOLUBLE COATINGS, PACKAGES AND METHODS FOR MAKING AND USING SAME Milton Freifeld, Boonton, N.J., and George G. Tauth, Palmerton, Pa., assignors to GAF Corporation, New York, N.Y. N0 Drawing. Continuation-impart of application Ser. No. 608,485, Jan. 11, 1967. This application Apr. 13, 1970,

Ser. No. 28,132

Int. Cl. (321d 17/00 US. Cl. 252-90 Claims ABSTRACT OF THE DISCLOSURE This invention is directed to coated compositions comprising granular detergent solids or detergent tablets coated with a water-soluble partial ester of (a) a nonionic hydroxyl-containing micelle-forming surface active agent and (b) a vinyl-maleic anhydride interpolymer, and

the process for producing said coated compositions.

This application is a continuation-in-part of copending application Ser. No. 608,485 filed Jan. 11, 1967, now abandoned.

This invention relates to methods for treating and/or handling gsolid materials and more particularly to the method for coating particulate deteregnt solids as well as tablets composed of compacted granular detergents to provide a protective layer thereover which is readily removable and does not interfere with the normal and usual performance and function of the granular detergents or tablets, and to the resultant treated solids and coated tablets produced thereby.

The recent advent of coated granular substances which are soluble in water along with similar products in tablet form has promoted the search and need for packaging materials which would not adversely alfect the function of the material so packaged and which would further be readily removable and/or disintegrable in the usual aqueous medium where such products as detergents and the like are employed. To be suitable as a packaging, i.e., coating substance as heretofore described, the material must obviously be of sufficient water solubility in the wash bath so that it dissolves or disintegrates within a reasonable time, i.e., within a minute or so after addition to the bath. On the other hand, the material should not be subject to high tack development or exhibit blocking tendencies under conditions of high humidity. It is, of course, further obvious that any material to be considered as a suitable film-former for such uses as instantly contemplated must be capable of forming continuous homogeneous films of reasonable strength to withstand normal handling and manufacturing procedures and should exhibit good stability on aging.

It is, therefore, an object of this invention to provide a method for coating, encasing and otherwise treating granular substances which are particularly intended for addition to aqueous systems.

It is another object of this invention to provide a method for providing a protective coating for granular detergents and detergent tablets and the like, with a watersoluble film-forming protective substance.

It is still another object of the present invention to provide coated granular solids to protect same and facilitate their handling for ultimate use in aqueous systems.

It is still another further object of this invention to provide a coated detergent tablet which is adapted for use in aqueous systems, which coated tablet is characterized by unusual stability of the active components of the material within the protective film.

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Other objects will appear hereinafter as the description proceeds.

It has now been discovered that the above objects may be readily obtained by utilizing water-soluble partial esters of vinyl-maleic anhydride interpolymers which are outstandingly adapted for use as film-formers and protective coatings for granular substances in general and more particularly for granular detergent materials, especially in the form of compacted tablets thereof. These partial esters are fully compatible with the typical detergent formulations, and impart certain desirable properties. Among these properties are enhanced ease of dispersion as well as the improvement of the feel of the detergent and the wash water, i.e., a soapy feel.

The aforementioned water-soluble partial esters and the method for their preparation is fully described in copending application, Ser. No. 176,906, filed Mar. 2, 1962, now US. Pat 3,301,829, the disclosure of which is hereby incorporated by reference thereto. In general, the Water-soluble partial esters are prepared from the interaction of hydroxy-containing micelle-forming surface active compounds as the alcoholic esterifying moiety and vinyl-maleic anhydride interpolymers as the carboxycontaining esterifying moiety. The hydroxy-containing compound comprises the general class of surface active agents of the nonionic type and more particularly, such nonionic compounds which are derived from reactive hydrogen-containing hydrophobes interacted with an alkylene oxide or equivalent thereof, and more particularly, interacted with ethylene oxide.

The water-soluble partial esters are produced, by virtue of the interaction of the anhydride moiety of the interpolymer with the hydroxyl group of the nonionic surface active material. In order to effect the production of watersoluble partial esters which are particularly adaptable for the uses herein contemplated, it is necessary that the surface active material contain from about 60% to about by weight combined alkylene oxide and that such surface active material be reacted with the maleic interpolymers in a weight ratio ranging from 20:1 to 1:6. It has been empirically determined that under the conditions above set forth, particularly with regard to the ratio of the reactants and where the reaction is carried out following the techniques hereinafter to be described, the resultant partial esters thereby produced contain no more than about 5% of the total carboxyl groups available from the interpolymer as ester groups. Within the parameters above outlined, it has been determined and found that the partial esters so produced are capable of forming water-soluble films by coating granular solids or tablets by the usual techniques, which films or coatings are characterized by the properties hereinabove described.

Thus, the instant invention may be described as being an improved process for coating granular detergent solids or detergent tablets. The improvement comprises employing as the coating material a water-soluble partial ester of (a) a nonionic hydroxyl-containing micelleforming surface active agent and (b) a vinyl-maleic anhydride interpolymer.

In addition, the instant invention :may be more specifically characterized as a coated composition comprising granular detergent solids or detergent tablets, coated with a water-soluble partial ester of (a) a nonionic hydroxylcontaining micelle-forming surface active agent and (b) a vinyl-maleic anhydride interpolymer.

The maleic anhydride interpolymers which may be used in producing the partial esters useful in the present invention are preferably derived from the equimolar polymerization of maleic anhydride or a substituted :maleic anhydride with a vinyl compound, and preferably a vinyl ether.

3 In addition to maleic anhydride, other o e-unsaturated dicarboxylic acid anhydrides of the maleic anhydride series may be used. Such compounds have the following general formula:

wherein R and R are independently selected from the group consisting of hydrogen, halogen, alkyl, aryl, aralkyl and substituted forms thereof, and sulfonic acid. Illustrative samples of suitable compounds coming within the above formula are in addition to maleic anhydride:

chloromaleic anhydride citraconic anhydride fumaric anhydride mesaconic anhydride phenyl maleic anhydride benzyl maleic anhydride sulfomaleic anhydride aconitric anhydride and the like.

The copolymerizable vinyl compound which may be used for interpolymerization with the maleic anhydride as pointed out above, is preferably an alkyl vinyl ether such as:

methyl vinyl ether ethyl vinyl ether n-propyl vinyl ether isobutyl vinyl ether isoctyl vinyl ether tetradecyl vinyl ether octadecyl vinyl ether and the like.

Generally, the alkyl vinyl ethers may contain any component chain length in the alkyl moiety and preferably from 1 to about 30 carbons therein. In addition, the alkyls may be substituted with the usual inert substituents such as halogen, alkoxy, acyloxy, and the like groupings.

It is also possible to employ in lieu of the vinyl ethers above described, other vinyl compounds which are readily and conventionally interpolymerized with maleic anhydride, and these include the general class of aromatic vinyl ethers, e.g.,

phenyl vinyl ether naphthyl vinyl ether vinyl esters, e.g.,

vinyl acetate vinyl propionate vinyl caproate vinyl stearate vinyl halides, e.g.,

vinyl chloride vinyl fluoride vinyl bromide acrylic acid and esters, e.g.,

methyl acrylate ethyl acrylate octyl acrylate, etc.

other acrylic acid derivatives, e.g.,

methacrylic acid and the conventional alkyl and substituted alkyl esters thereof acrylonitrile methacrylonitrile acrylamide and methacrylamide N-vinyl lactams, e.g.,

N-vinyl pyrrolidone N-vinyl-3-morpholinone N-vinyl oxazolidone, etc., and the alkyl ring substituted derivatives of these lactams styrene alkyl styrenes vinylidene chloride alkyl vinyl ketones, e.g. methyl vinyl ketone olefins, e.g.,

ethylene propylene isobutylene hexane-1, etc.

While the interpolymers which are preferred herein contain the two comonomers in equimolar amounts whereby the repeating unit in the interpolymer contains one anhydride and one vinyl moiety, it is also possible to produce and employ interpolymers wherein the said moieties are present in the molar ratio ranging from 5:4 to 4:5. The most preferred interpolymers are the methyl vinyl ethermaleic anhydride interpolymers containing comonomers in a 1:1 ratio.

The interpolymers above described, may vary in molecular Weights from as low as about 400 to several million (e.g. 2,000,000) or more. Viscosity measurements are commonly used as an indication of the average molecular weight of the polymeric composition. The K value (Fikentscher) of any particular mixture of polymers is calculated from viscosity data and is useful as an indication of the average molecular weight of such mixture. Its determination is fully described in Modern Plastics, 23, No. 3, 157-61, 212, 214, 216, 218 (1945) and is defined as 1000 times k in the empirical relative viscosity equation:

wherein C is the concentration in grams per hundred cc. of polymer solution and 1 is the ratio of the viscosity of the solution to that of pure solvent. The K values are reported as 1000 times the calculated viscosity coefficient in order to avoid the use of decimals. The preferred interpolymers employed in the present invention have K values of from about 10 to about 200.

K values and specific viscosities (1; sp) are interconvertible and are related through relative viscosity (1 rel). Thus, when viscosity measurements are taken on solutions which have a concentration of 1.00 gram of polymer per deciliter of solution at 25 C. (C=1), the relationships are as follows:

0 rel=1 sp+1 Relative viscosity=specific viscosity plus one.

Relative viscosity: 10(0.00lK+0.000075K l +0.0015) Hence 1 =1+l0(0.001K+0.000075K /(1+0.0015K) Relative viscosity, specific viscosity and K are dimensionless, whereas inherent viscosity e 7ml) C and intrinsic viscosity (the limit of inherent viscosity as C approaches zero) have the dimensions of dilution, i.e., the reciprocal of concentration. Intrinsic viscosity and K are intended to be independent of concentration. The preferred interpolymers are those having a specific viscosity ranging from about 0.1 to about 4.5.

The nonionic surface active hydroxy-containing esterforming products which may be used to produce the partial esters are well known micelle-forming surface active agents especially those alkylene oxide condensation prodnets with an active hydrogen containing hydrophobe which are preferably derived from aliphatic or aromatic-containing hydroxy compounds, i.e., alcohols or phenols which have been reacted with the requisite quantity of alkylene oxide to yield polyoxyalkylated alkyl phenols and alkyl poly(alkylenoxy) alkanols containing from about 55, preferably about 60 to 90% by weight of combined alkylene oxide.

By the term alkylene oxide, applicants mean those oxides having from 2 to 4 carbon atoms such as propylene oxide, butylene oxide, isobutylene oxide and preferably ethylene oxide as well as mixtures of such oxyalkylating agents which may be used simultaneously or in sequence. The general procedure for the preparation of such com pounds is well known as well as the products per se. Examples thereof may be found in U.S. Pats. 1,970,578 and mon others. 52222 :lcoho ls and phenols which may be used for interaction and condensation with ethylene oxide, for example, include the following:

nonylphenol (propylene trimer) octylphenol (diisobutylene) dodecyl phenol (propylene tetramer) diamylphenol dibutylphenol alkylphenols (where alkyl is C; to C alkyl cresols (where alkyl is 0., to C mixed coco alcohols lauryl alcohol (85% C alcohol) castor oil lauryl alcohol (92% C alcohol) tridecyl (oxo) alcohol oleyl alcohol hydrogenated tallow alcohol ROH prepared from olefins of C to C by the oxo process, i.e., addition of R C O and hydrogenation to the alcohol ROH where R=C to C Where R=n-C H t l'l-C22H45 and R1208 to H22 X-OH or X-('OH) +propylene oxide to MW 800 to 2500 where X=residue of active hydrogen compound.

tAlkylolamine condensation products with fatty acids or esters are also suitable as hydroxyl-containing compounds. Suitable alkylolamines include:

diethanolamine monoethanolamine isopropanolamine di-n-propanolamine Glycol and polyol esters of fatty acids can also be used.

The reaction for the production of the partial esters of and useful in this invention may be carried out in water or in an organic solvent at room temperature or at slightly elevated temperatures. Where water is employed as the reaction solvent, it is preferred to first dissolve the hydroxy surface active compound in the water and to this solution to add, with stirring, the anhydride form of the interpolymer, usually as a finely divided polymer. Where an inert non-reactive organic solvent is used in place of water (e.g., acetone) the order of addition of reactants is not critical. Complete reaction takes place within about 24 hours at room temperature and at much shorter periods of time at somewhat elevated temperatures, e.g., within 45 minutes at 70 C. Where water is employed as the solvent for the partial ester formation, any amount may be used up to about 99% by weight of the total weight of the reaction mass. The minimum water content is not critical but is governed solely by viscosity considerations, since at high solids content and low water concentrations the partial esters which are produced form an extremely viscous mass. In general, it is preferred when operating in aqueous medium, to provide a solids content of partial ester ranging from about 1% to about 10% by weight. Within such a range of solids concentration, it has been found that the viscosity characteristics are such as to provide for reasonable and feasible handling of the composltions.

While the immediate and most advantageous use of the compounds with which this invention is concerned lies in the coating of detergent solids and similar products, particularly detergent tablets, it is equally clear that protective coatings may be applied to any solid by any of the well-known and conventional methods. Thus, a solution of the polymer may be applied directly to an article, material, compound and the like, by brushing, dipping, spraying, roller coating, etc., followed by a conventional air drying or baking to remove the solvent. Moreover, if desired, protective coatings may be reinforced or modifired by first blending with natural and synthetic gums, SlZlllgS or other coatings.

The useful detergents which may be coated according to the present invention include anionic detergents such as alkylbenzenesulfonic acid and its salts, and compounds of the formula alkyl-phenyl-sO -M, wherein alkyl is an alkyl radical of a fatty acid and M is hydrogen or an alkali metal, which compounds comprise a well-known class of anionic detergents and include sodium dodecyl benzene sulfonate, potassium dodecylbenzenesulfonate, sodium laurylbenzenesulfonate, sodium cetylbenzenesulfonate. Others are the alkali metal dialkyl sulfosuccinates, e.g., sodium dioctylsulfosuccinate, sodium dihexylsulfosuccinate, sodium sulfoethylphthalate, sodium laury-p-anisidinesulfonate, sodium tetradecanesulfonate, sodium disopropylnaphthalenesulfonate, sodium octylphenoxyethoxyethylsulfonate, etc.; and the alkali metal alkyl sulfates, e. g., sodium lauryl sulfate.

Among the above-noted alkylbenzenesulfonic acid and salts thereof, the preferred compounds included those which are biodegradable and which are particularly characterized by a linear alkyl substituent of from C to C and preferably from C to C It is, of course, understood that the carbon chain length represents, in general, an average chain length since the method for producing such products usually employs alkylating reagents of mixed chain length. It is clear, however, that substantially pure olefins as well as alkylating compounds used in other techniques can and do give alkylated benzene sulfonates wherein the alkyl moiety is substantially (i.e., at least 9%) of one chain length, i.e., C C C or C The linear alkyl benzene sulfonates are further characterized by the position of the benzene ring in the linear alkyl chain, with any of the position isomers (i.e., al ha to omega) being operable and contemplated.

The linear alkyl benzene sulfonates are generally and conveniently prepared by sulfonating the corresponding alkyl benzene hydrocarbons which in turn may be prcpared by alkylating benzene with a linear alkyl halide, a l-alkene or a linear primary or secondary alcohol. Pure isomers (of the l-phenyl isomer) are prepared by reduction of the acylated benzene (alkyl phenyl ketone) using a modification of the Wolif-Keshner reaction. The 2-phenyl isomer is obtained from n-undecyl phenyl ketone and methyl magnesium bromide to form the tertiary alcohol which is dehydrated to the alkene and then hydrogenated. The S-phenyl isomer is obtained similarly from a n-heptyl phenyl ke'tone and n-butyl magnesium bromide. The other isomers are obtained in a similar manner from the appropriate n-alkyl phenyl ketone and n-alkyl magnesium bromide.

In addition to the benzene sulfonates, one may also employ the lower alkyl (C to C analogs of benzene such as toluene, xylene, the trimethyl benzenes, ethyl benzene, isopropyl benzene, and the like. The sulfonates are generally employed in the water soluble salt form, which includes as the cation the alkali metals, ammonium, and lower amine and alkanolamine.

Examples of suitable linear alkyl benzene sulfonates are:

sodium n-decyl benzene sulfonate sodium n-dodecyl benzene sulfonate sodium n-tetradecyl benzene sulfonate sodium n-pentadecyl benzene sulfonate sodium n-hexadecyl benzene sulfonate and the lower corresponding lower alkyl substituted homologues of benzene as well as the salts of the cations previously referred to. Mixtures of these sulfonates may, of course, also be used with mixtures which may include compounds wherein the linear alkyl chain is smaller or larger than indicated herein provided that the average chain length in the mixture conforms to the specific requirements of C to C The linear paraflinsulfonates are also a well-known group of compounds and include water soluble salts (alkali metal, amine, alkanolamine, and ammonium) of:

l-decane sulfonic acid l-dodecane sulfonic acid l-tridecane sulfonic acid l-tetradecane sulfonic acid l-pentadecane sulfonic acid l-hexadecane sulfonic acid as well as the other position isomers of the sulfonic acid group.

In addition to the paraffin sulfonates illustrated above, others with the general range of C to C alkyls may be used, with the most preferable range being from C to C20.

The linear alkyl sulfates which are contemplated in this invention comprise the range of C to C Specific examples include sodium n-decyl sulfate, sodium n-dodecyl sulfate, sodium n-octadecyl sulfate, and the ethoxylated (l to 100 moles ethylene oxide) derivatives, and, of course, the other Water soluble salt-forming cations mentioned above.

The composition of the present invention may also include, in addition to the conventional anionic detergent compositions, builders, brighteners, hydrotropes, germicides, soil suspending agents, anti-redeposition agents, antioxidants, bleaches, coloring materials (dyes and pigments), perfumes, water soluble alcohols, non-detergent alkali metal benzene sulfonates, fabric softening compounds, enzymes, etc.

The builder is, generally, a water soluble, inorganic salt which may he a neutral salt; e.g., sodium sulfate or an alkaline builder salt such as phosphates, silicates, bicarbonates, carbonates, and borates. The preferred builders are those characterized as condensed phosphates such as polyphosphates and pyrophosphates. Specific examples of alkaline salts are: tetrasodium pyrophosphates, pentasodium tripolyphosphate (either Phase I or Phase 11), sodium hexametaphosphate, and the corresponding potassium salts of these compounds, sodium and potassium silicates; e.g., sodium metasilicate and alkaline silicates (Na O; 2SiO and Na O; 3SiO sodium carbonate, potassium carbonate and sodium potassium bicarbonate.

Other salts may also be used where the compounds are water soluble. These include the general class of alkali metal, alkaline earth metal, amine, alkanolamine, and ammonium salts. Other builders which are salts of organic acids may also be used, and in particular the water soluble (alkali metal, ammonium, substituted ammonium and amine) salts of aminopolycarboxylic acids such as:

ethylene diamine tetra-acetic acid nitrilo triacetic acid diethylene triamine penta-acetic acid N-(2-hydroxyethyl)-ethylene diamine triacetic acid 2-hydroxyethyl-iminodiacetic acid 1,2-diaminocyclohexane diacetic acid, and the like.

In addition to the above ingredients, one may as previously delinated employ hydrotropes in connection with the compositions of the instant invention. The useful hydrotropes include such compounds as sodium xylene sulfonate, potassium xylene sulfonate, sodium and potassium toluene sulfonates, in the position isomers thereof, and ethyl benzene sulfonate.

The nonionic surface active agents which may be coated according to this invention are well known in the art and are disclosed along with suitable methods for their preparation in numerous patents and other publications. In general, they may be obtained by condensing a polyglycol ether containing the required number of alkenoxy groups or an alkylene oxide such as propylene oxide, butylene oxide, or preferably ethylene oxide, or mixtures thereof, with an organic compound containing at least 6 carbon atoms and a reactive hydrogen atom. As such compounds containing a reactive hydrogen atom there may be mentioned alcohols, phenols, thiols, primary and secondary amines, and carboxylic and sulfonic acids and their amides. These compounds may obviously contain more than one reactive hydrogen atom, i.e., more than one hydroxy, mercapto, amino, amido, carboxylic, sulfonic or sulfonamido group, each such group in the compound being reactive with the alkylene oxide in suitable proportions. The amount of alkylene oxide or equivalent condensed with the reactive hydrogen-containing compound, i.e., the length of the polyoxyalkylene chain, will depend primarily upon the particular compound with which it is condensed. As a convenient rule of thumb, an amount of alkylene oxide or equivalent should be employed which will result in a condensation product containing about 20 to by weight of combined alkylene oxide. However, the optimum amount of alkylene oxide for attainment of the desired hydrophobic-hydrophilic balance may be readily determined in any particular case by preliminary test and routine experimentation.

The reaction between the reactive-hydrogen-containing organic compound and the alkylene oxide in the production of the above described nonionic surface active agents is well known in the art, being preferably carried out at elevated temperatures and pressures and catalyzed by quaternary hydroxides, amines, acids and/or coordinating type compounds although strong alkaline catalysts such as KOH or NaOH and the like arc preferred because of fewer by-products formed and the more easily controlled reaction conditions. The reaction is substantially quantitative, although it will be understood that the product of this reaction between the alkylene oxide, preferably ethylene oxide, and the organic reactive hydrogen-containing compound will be a mixture of polyoxyalkylene derivatives of varying oxyalkylene chain length, the average of which substantially corresponds to the amount of alkylene oxide reactant. Such product will of course always contain an average of at least one hydroxy group (in a terminal --C H OH group) per molecule.

In the production of the above described nonionic surface active agents, the following are illustrative examples of types of organic compounds containing a reactive hydrogen atom:

(1) Aromatic monoand poly-hydroxy compounds such as phenols, naphthols, benzene and naphthalene diols, triols and tetrols and the like. In this group, alkyl phenols are preferred containing 1 to 3 alkyl substituents of from 4 to 20 carbon atoms each. Some examples of such compounds are the normal and isomeric mono-, di-, and tri-butyl, -nnyl, and octadecylphenols and cresols, and phenols and cresols substituted by a plurality of different such alkyl groups.

(2) Straight and branched chain, saturated and unsautrated aliphatic monohydric and polyhydric alcohols of natural or synthetic origin. Among this group are the alcohols derived from animal and vegetable sources such as lauryl alcohol, stearyl alcohol, and the like. Also included are the diol precursors of the Pluronic type nonio nic surface active agents, generally prepared by polyoxyethylena-tion of a polymerized alkylene oxide of at least 3 carbon atoms, preferably propylene oxide, to produce the corresponding water insoluble polypropylene glycol having a molecular weight of up to about 3000, or of the reaction product of a plurality of moles of propylene oxide or substituted propylene oxide with alkylene diamines such as ethylene diamine and propylene diamine, polyalkylene polyamines, and alkane diols such as ethylene glycol, hexamethylene glycol, and the like. These agents of the Pluronic type may range in molecular weight from about 300 to 10,000. This group also includes the primary aliphatic alcohols containing a plurality of side chains. Such multi-branched chain alcohols may be produced by various methods, preferably by subjection of an olefin containing at least 7 carbon atoms and at least 2 side chains, such as tripropylene, tetrapropylene, pentapropylene, diisobutylene, triisobutylene, and the like to the 0x0 process, involving the catalytic reaction of the olefin with carbon monoxide and hydrogen to form an aldehyde followed by catalytic reduction of the aldehyde to the corresponding primary alcohol. Other alcohols in this group are the essentially straight chain alcohols produced from Fischer-Tropsch olefins by the Oxo process or those produced by oxidation of Ziegler type polymer intermediates. Such intermediates, or mixtures thereof, made by polymerizing ethylene with a metal (e.g., aluminum) alkyl, have an even. number of carbon atoms averaging 10 to 24 per molecule in the chain.

(3) Higher fatty acids of animal and vegetable origin and mixtures containing the same, such as lauric acid, oleic acid, stearic acid, the animal and vegetable fats and oils containing same, or the acids derived by oxidation of suitable petroleum fractions.

(4) Aliphatic and aromatic monoand poly-mercapto compounds including cetyl mercaptan, dodecyl mercaptan, alkyl naphthylamine, alkyl thiophenol, thionaphthol, and the like.

(5) Aliphatic and aromatic monoand poly-amines, including laurylamine, stearylamine, alkyl benzylamine, alkyl naphthylamine, dodecylene diamine, tetrapropylene pentamine, and the like.

(6) Carboxylic acid amides such as lauric acid amide, stearic acid amide and the like.

(7) Sulfonamides and such as dodecyl sulfonamide, dodecylbenzene sulfonamide, and the like.

These and other types of organic compounds containing reactive hydrogen atoms suitable for reaction with alkylene oxides are disclosed for example in US. Pats. 1,970,578; 2,002,613; 2,085,706; 2,174,761; 2,205,021; 2,213,477; 2,266,141; 2,593,112; 2,674,619; 2,677,700; 2,766,212 and others.

The following is an illustrative, non-limitative list of some specific examples of suitable nonionic surface active agents which may be employed as detergents in the present invention. In this list, E.O. means ethylene oxide and the number preceding same refers to the number of moles thereof reacted with one mole of the given reactive hydrogen-containing compound.

Nonylphenol +9-11E.O. Do +2 E.O. Dinonylphenol +7 E.O. Dodecylphenol +18 E.O. Castor oil +20 E.O. Tall oil +18 E.O. Oleyl alcohol +18 E.O. Lauryl alcohol +4 E.O. Do +15 E.O. Hexadecyl alcohol +12 E.O. Do +20 E.O. Octadecyl alcohol +20 E.O. Oxo tridecyl alcohol (from tetrapropylene) +7 E.O. From tetrapropylene +10E.O. From tetrapropylene +15 E.O. Dodecyl mercaptan +9 E.O. Soya bean oil amine -Q- +10E.O. Rosin amine +32 E.O. Cocoanut fatty acid amine +7 E.O. Cocoa fatty acid +10 E.O. Dodecylbenzene sulfonamide +10E.O. Decyl sulfonamide +6 E.O. Oleic acid +5 E.O.

Polypropylene glycol (30 oxypropylene units)- 10 B0.

In the following examples, commercial detergent tablets were tested with the coatings of the present invention. The tablets used were Quik-Solv and Salvo which are products of the Colgate-Palmolive Co. and Procter and Gamble, respectively. Such detergent tablets, or briquettes, as with granular or powdered detergents, can be of the anionic or nonionic detergent type. Typical formulations of such products are as follows:

Ingredient: Parts by weight Ethoxylated nonyl phenol (9-10 E.O.) 10.0 Sodium tripolyphosphate 30.7

Sodium silicate (Na O:SiO ratio of 1:2.35) 30.3 Sodium sulfate 6.6

Sodium silicate (SiO :Na O=3.22: 1) 10.75

Sodium sulfate 42.0 Magnesium oxide 0.75 Sodium carboxymethylcellulose 1.0

The following examples are illustrative of the present invention and are not to be regarded as limitative. It is to be understood that all parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise indicated.

EXAMPLE 1 To g. of water there was added with stirring, 10.6 g. of a condensate produced from 1 mol of nonyl phenyl reacted with about 9.5 mols of ethylene oxide. After solution of the surfactant had been effected, there was then added with continuous stirring and while heating as a steam bath at 75 C. and until all of the additive had been dissolved, 9.4 g. of an interpolymer of methyl vinyl ether and maleic anhydride (specific viscosity=1.4 molar ratio of comonomer 1:1). After about 1 hour the resultant solution (10% solids) was diluted with water to 5% solids. This composition was then sprayed on several commercial detergent tablets to yield clear, transparent, non-tacky protective coatings thereon.

1 1 EXAMPLE 2 The procedure of Example 1 was repeated except that the amount of surface active agent used was 19 g. of a condensate produced from 1 mol of nonyl phenol reacted with about 30 mols of ethylene oxide and the amount of interpolymer is 1 g. This composition also produced clear, transparent, non-tacky protective coatings when sprayed on commercial detergent tablets.

EXAMPLE 3 The coated tablets produced in Examples 1 and 2 were then compared with an uncoated tablet for initial solubility in water as well as for solubility in water after the three samples had been heated to 140 F. for 4 weeks. The uncoated tablet initially required 2.5 minutes to achieve complete solubility but 22 minutes after the 4 weeks heat test. The coated products of Examples 1 and 2 took 3 minutes to dissolve initially and after the 4 weeks heat test, the product of Example 1 was found to take 4 minutes to achieve complete solubility and the product of Example 2 was found to take only 2 minutes to accomplish complete dissolution.

This comparison aptly demonstrates the excellent solubility and improved stability on aging attributed to the deposited protective coating on the detergent tablets.

It was also found that the impact resistance of the coated tablets of Examples 1 and 2 is about 40% greater than that of the uncoated tablets, both before and after the heating test.

EXAMPLE 4 Example 1 was repeated employing the following weight ratios of interpolymer to surface active agent of 1:2, 2:1, 1:1. All 3 compositions yielded clear, .glossy, non-tacky protective coatings on the detergent tablets and the final products exhibited very good solubility and stability on aging.

EXAMPLE 5 Example 1 was again repeated, except that a surface active condensation agent product from 1 mol of nonyl phenol reacted with about 100 mols of ethylene oxide was used and the weight ratio of interpolymer to the surfactant was 1:1. Clear, glossy, non-tacky protective coatings were obtained on detergent tablets and the coated tablets exhibited very good solubility and stability upon aging.

Like results may be obtained by replacing the interpolymer with the following interpolymers in which the monomers are present in equimolar amounts:

(A) chloromaleic anhydride-vinyl methyl ether (X=30) (B) chloromaleic anhydride-vinyl methyl ether (K:60)

(C) citraconic anhydride-vinyl methyl ether (K=40) (D) methylene malonic anhydride-vinyl methyl ether (E) benzyl maleic anhydride-vinyl methyl ether (K=35) (F) maleic anhydride-vinyl ethyl ether (K=20) (G) maleic anhydride-vinyl ethyl ether (K=90) (H) maleic anhydride-vinyl isobutyl ether (K=40) (I) maleic anhydride-vinyl acetate (J) maleic anhydride-vinyl stearate (K) maleic anhydride-vinyl chloride (L) maleic anhydride-methyl acrylate (M) maleic anhydride-acrylonitrile (N) maleic anhydride-N-vinyl pyrrolidone (O) maleic anhydride-styrene (M.W.=2300) (P) maleic anhydride-ethylene (sp. via. l.0-1% in dimethyl formamide) (Q) maleic anhydride-propylene (R) maleic anhydride-styrene-vinyl acetate.

Moreover, similar results may also be produced by replacing the surface active agents in the above examples with the following nonionic sufactants:

(A) nonyl phenol-H5 mols ethylene oxide (B) dinonyl phenol+24 mols ethylene oxide (C) dodecyl phenol+ 10 mols ethylene oxide (D) nonyl phenol-{-10 mols propylene oxide (E) nonyl phenol+20 mols propylene oxide (F) nonyl phenol+11 mols butylene oxide (G) nonyl phenol+15 mols ethylene oxide+10 mols butylene oxide (H) n-octyl phenol+l5 mols ethylene oxide (I) dodecyl phenol+7 mols ethylene oxide+3 mols butylene oxide (J tri-octadecyl phenol+30 mols ethylene oxide (K) lauryl alcohol+10 mols propylene oxide (L) oleyl alcohol+20 mols ethylene oxide (M) tridecyl alcohol+6 mols ethylene oxide (N) tridecyl alcohol+9l0 mols ethylene oxide tridecyl alcohol-H mols ethylene oxide (P) tridecyl alcohol+10 mols butylene oxide (Q) hexadecyl alcohol+ mols ethylene oxide (R) C -C alcohol admixture-{-10 mols admixture of 80% ethylene oxide and propylene oxide.

EXAMPLE 6 Samples of Quik-Solv detergent briquettes were sprayed with a partial ester prepared as in Example 1 and compared with briquettes sprayed with Lemofiex, which is an ethoxylated polyvinyl alcohol, as well as with control, untreated, briquettes.

Six of each of the briquettes were sealed in polyethylene bags and six were left open to the atmosphere. All the briquettes were placed in a constant temperature and humidity room at 70 F. and relative humidity. Two of each sample were tested for solubility at two month intervals. The solubility tests determined the solution time in 4 gallons of water at 100 F. The results were as follows:

2 months 4 months 6 month Control:

Exposed, min, 78. 0 87.0 120 0 92.0 70.0 112.0 Bagged, min, 6. 0 5. 5 5. 0 Do 6. 5 6. 0 5. 0 Lemotlex:

Exposed, min 121.0 165. 0 178. 0 D0 165.0 115.0 130. 0 Bagged, min 0. 5 2.0 6. 5 Do 4. 5 3. 5 4. 5 Partial ester:

Exposed, min... 00. 0 80. 0 15. 0 D0 05. 0 85.0 83. 0 Bagged, min. 6. 0 3. 0 4. 0 Do 5. 0 2. 0 3. 0

Thus, it can be seen that the partial ester coating according to this invention provided solubility characteristics at 2, 4 and 6 months equal to, or better than, the uncoated briquettes. Further, the partial ester coated briquettes demonstrated better solubility characteristics than the ethoxylated polyvinyl alcohol coated briquettes.

Various modifications and variations of this invention will be obvious to a worker skilled in the art and it is understood that such modifications and variations are to be included within the purview of this application and the spirit and scope of the appended claims.

We claim:

1. In a method for coating anionic or nonionic detergent solids in granular or tablet form with a protective film, the improvement which comprises coating said detergent solids with a protective coating consisting essentially of a watersoluble partial ester formed by the reaction of (a) a nonionic hydroxyl-containing micelle-forming surface active agent and (b) a vinyl-maleic anhydride interpolymer, said surface active agent being an alkylene oxide condensation product of an active hydrogen-containing hydrophobe and having a combined alkylene oxide content of from about to about by weight, said interpolymer having a molar ratio of vinyl moiety to maleic anhydride of from 5:4 to 4:5, the weight ratio of said surface active agent to said interpolymer being from 20:1 to 1:6.

2. A process as defined in claim 1, wherein the detergent solids are in tablet form.

3. A process as defined in claim 1, wherein the interpolymer is a methyl vinyl ether-maleic anhydride interpolymer.

4. A process as defined in claim 3 wherein the watersoluble partial ester is a partial ester of (a) an ethylene oxide condensation product with nonyl phenol and (b) methyl vinyl ether-maleic anhydride interpolymer.

5. A process as defined in claim 1, wherein said surface active agent is an alkylene oxide condensation product of a member of the group consisting of aliphatic alcohols of from 8 to 22 carbon atoms and alkyl phenols containing 4 to 22 carbon atoms in the alkyl groups.

6. A process as defined in claim 1, wherein the ratio of vinyl moiety to maleic anhydride is 1: 1.

7. A process as defined in claim 1, wherein said alkylene oxide content is from about 60% to about 90%.

8. A composition consisting essentially of an anionic or nonionic detergent solid in granular or tablet form having 14 by weight, said interpolymer having a molar ratio of vinyl moiety to maleic anhydride of from 5:4 to 4:5, the weight ratio of said surface active agent to said interpolymer being from 20:1 to 1:6.

9. A composition as defined in claim 8, wherein the detergent solid is in tablet form.

10. A composition as defined in claim 8 wherein the protective coating is a water-soluble partial ester of (a) an ethylene oxide condensation product with nonyl phenol and (b) a methyl vinyl ether-maleic anhydride interpolymer.

References Cited UNITED STATES PATENTS 2,990,398 6/1961 Inskip et al. 2,301,829 1/ 1967 Woodward et al. 3,379,554 4/1968 Brindamour.

FOREIGN PATENTS 510,555 3/1955 Canada.

LEON D. ROSDOL, Primary Examiner W. E. SCHULZ, Assistant Examiner U.S. Cl. X.R.

117100; 252Digest 3 

